The present invention relates generally to bicycle shifters, and more particularly, is directed to a shifter for a bicycle using a dual action lever which moves in the same motion as the natural movement of the thumb.
Conventionally, shifts for bicycles have been mounted on the handlebar. However, in order to actuate the shift lever, the thumb and/or index finger must be removed from the handlebar. This severely weakens the grip and can be dangerous, for example, when riding a mountain bike over very bumpy roads and/or traveling at a high speed.
Related to this problem is the fact that conventional levers, during actuation, do not follow the natural movement of the thumb. This, again, weakens the grip.
It is therefore desirable to maintain a tight grasp with all fingers, including the thumb, on the handlebar at all times, even when shifting.
Further, many conventional shifters require the use of the index finger to actuate the lever. This, however, is the same finger used to actuate the brake lever, which is disadvantageous.
Although there are shifters that maintain the grip but change gears by rotating the grip, these are disadvantageous because they require bending of the wrist, and thereby weaken the connection to the handlebar.